Severe childhood obesity has become an alarming issue in pediatric care but no population-based studies exist to quantify the number of severely obese children and the resulting adverse health consequences. Recent data from the Bogalusa Heart Study suggest that cardiovascular risk factors increase with severity of obesity but this conclusion was only based on few children that were severely obese. The 2007 revised recommendations regarding childhood obesity include specific weight goals and treatment for severely obese children that are at or above the 99th percentile of body mass index (BMI)-for-age according to the 2000 sex-specific Centers for Disease Control and Prevention growth charts. However, we lack information on the prevalence of obesity-related complications among severely obese children and disparities regarding age, sex and race/ethnicity. For the first time in two centuries, life expectancy may decline due to the rapidly increasing prevalence of obesity. Considering that arthrosclerosis, glucose intolerance and hepatic disease begin at an early age, without early intervention these children may be at high risk in adulthood. Therefore, we propose a cross-sectional study of over 700,000 children including over 95,000 children who are at or above the 97th percentile of BMI- for-age and over 40,000 children who are at or above the 99th percentile of BMI-for-age. All children are insured within a large managed care system and have equal access to health care, including standardized screening guidelines for overweight and obese children. The specific aims for this study are to (1) estimate the association between severity of obesity and adverse health outcomes such as endocrine disorders, gastrointestinal problems, and cardiovascular risk factors and (2) examine the modification of the association between the severity of obesity and adverse health conditions by demographic factors such as sex, race/ethnicity, and age. As a secondary aim, we will investigate predictors of screening for adverse health conditions. Thus, the proposed study takes advantage of a large existing data set at Kaiser Permanente Southern California extracted from electronic medical charts. The investigators bring a unique combination of expertise that will greatly enhance the project's ability to provide solid information on the implications of extreme childhood obesity to develop specific guidelines for screening and aggressiveness of treatment. PUBLIC HEALTH RELEVANCE: For the first time in two centuries, life expectancy may decline due to the rapidly increasing prevalence of obesity. Childhood obesity has been linked to increased risk for cardiovascular risk factors as well as endocrine and gastrointestinal disorders. The proposed project will specify the risk for complications according to the severity of obesity (simple to extreme obesity) and contribute information for screening and treatment recommendations of obese children.